Chemical Physics Letters (v.499, #1-3)

Contents (iii-xii).

Uncertainty quantification: Making predictions of complex reaction systems reliable by Trent Russi; Andy Packard; Michael Frenklach (1-8).
Display Omitted► A predictive model must satisfy numerous experimental and theoretical constraints. ► Most current methods for problems of high dimension invoke approximations. ► Data Collaboration, a method of uncertainty quantification, deals effectively with these constraints. ► The analysis shows that seemingly ‘harmless’ methodological approximations could lead to substantial differences in the accuracy of model predictions.There is increasing need to make chemical reaction models and modeling more predictive. We examine the modeling methodology from the perspective of propagation of uncertainties, those in assumed model parameters along with those in experimental observations. Accepting the length of the uncertainty interval in the predicted property as a measure of model predictiveness, we examine methodological factors affecting it. Employing the recently introduced technique of Data Collaboration, we show that even ‘harmless’ assumptions, invoked explicitly or implicitly to alleviate a burden of numerical procedures, could lead to substantial differences in model predictiveness. We also demonstrate that the direct, one-step methodology, such as Data Collaboration, necessarily makes modeling more predictive and thus more reliable than a two-step approach typical of most current methods.

A practical implementation of semi-classical transition state theory for polyatomics by Thanh Lam Nguyen; John F. Stanton; John R. Barker (9-15).
.Display Omitted►Both canonical and microcanonical rate constants. ►Fully-coupled vibrational anharmonicities for transition states using CCSD(T). ►ab initio rate constants in excellent agreement with experiments.An algorithm is described for computing rate constants with semi-classical transition state theory (SCTST) formulated by Miller and coworkers. SCTST incorporates non-separable coupling among all degrees of freedom and multi-dimensional quantum mechanical tunneling along the curved reaction path. The algorithm, which is practical for reactants containing dozens of atoms, predicts both microcanonical and canonical rate constants. In addition, the quantum chemistry code CFOUR has been extended to efficiently compute fully-coupled vibrational anharmonicities for transition states at the CCSD(T) level of theory. The new methods are demonstrated for the H2  + OH reaction and the ‘tail-biting’ isomerization of acetylperoxyl radical.

H3N⋯Ag–Cl: Synthesis in a supersonic jet and characterisation by rotational spectroscopy by Victor A. Mikhailov; David P. Tew; Nicholas R. Walker; Anthony C. Legon (16-20).
Display Omitted► Synthesis of symmetric-top molecule H3N⋯Ag–Cl in gas phase. ► Monoammoniate of transition metal salt. ► Comparison of properties from rotational spectrum and ab initio calculation.The monoammoniate of silver monochloride, H3N⋯Ag–Cl, has been synthesised by laser ablation of metallic silver in the presence of a dilute mixture of NH3 and CCl4 in argon. The rotational spectra of five symmetric-top isotopologues were observed using a pulsed-jet, F-T microwave spectrometer that incorporates a laser-ablation source. Rotational constants B 0, centrifugal distortion constants DJ and DJK , and Cl and 14N nuclear hyperfine coupling constants were determined. r 0 and r s values of the N–Ag and Ag–Cl internuclear distances are reported and compared with r e quantities obtained by ab initio calculations at the CCSD(T)/cc-pVQZ level of theory.

Display Omitted► Influence of the electronic structure of endoperoxides in the UV absorption spectrum and photochemical paths leading to rearrangement products and singlet oxygen. ► O–O photolysis deactivation pathway in benzene endoperoxide. ► Characterization of a four state conical intersection. ► Obtention of the 9th dimensional branching space of the 4th order intersection point.The radiationless decay process connected to the breaking of the O–O bridge in benzene endoperoxide has been investigated using high-level ab initio multiconfigurational MS-CASPT2//CASSCF methods. The homolytic rupture of the O–O bond is controlled by a four-state conical intersection. The nine vectors which define the branching space of this high-order degeneracy point have been extracted from two-state conical intersection calculations between the electronic states involved in the degeneracy. The existence of four-state conical intersections indicates that, in general, endoperoxides can deactivate through very efficient radiationless funnels.

Display Omitted► The role of the nitrogen, phosphorus and arsenic substitution of the ring C–H groups of 1,3,5-trimethylenebenzene triradical was systematically studied using high level multi-reference and density functional methods. High-spin–low-spin gaps, electronic structure and chemical bonding were investigated. ► It was showed that the high-spin–low-spin gap can be tuned using chemical modification of the molecule. ► Also the spatial distribution of the unpaired electrons can be tuned by chemical modification. These provide a potential application in the design of molecular magnets. ► The results are interpreted with the aid of the Wiberg indices and the electron localization function.Substitution of C–H groups in 1,3,5-trimethylenebenzene (1,3,5-TMB) triradical by one, two or three N, P and As atoms is studied using CASSCF/CASPT2 computations with a ANO-RCC triple-ζ basis set. The computations showed that consistently with the previous results, the unpaired electrons in 1,3,5-TMB are highly delocalized, but our computations show that they become localized on the P and As atoms, with a more pronounced localization effect of As. All studied compounds have a quartet ground state, but the results showed in this Letter indicate that the quartet–doublet energy gap is reduced upon substitution. Localization of the unpaired electrons on the ring reduces the average distances between them, which induces a destabilization of the quartet states compared to the doublet. Therefore the position of the unpaired electrons and the doublet–quartet gap can be tuned by chemical methods, which opens the way to fine-tune the properties of the building blocks of organic magnets.

Display Omitted► Three types of angular distribution observed. ► Isotropic, anisotropic parallel and anisotropic perpendicular to the laser polarization. ► The anisotropic angular distributions have threshold like character for each ion observed. ► Electron impact ionization proved to be of significant importance.The angular distribution of the fragment ions ejected from the interaction of methyl iodide clusters with 20 fs strong laser pulses is studied by means of a mass spectrometer. Three types of angular distributions, one isotropic and two anisotropic, have been observed and their dependence on the laser intensity has been studied. There is strong evidence that the ions exhibiting anisotropic angular distribution with a maximum in the direction parallel to the laser polarization vector are produced via an electron impact ionization process.

The 41 Σ + electronic state of KLi molecule by J. Szczepkowski; A. Grochola; W. Jastrzebski; P. Kowalczyk (36-39).
Display Omitted► The 41 Σ +  ← X1 Σ + band system of KLi observed by polarisation labelling spectroscopy. ► The irregular potential curve of the 41 Σ + state constructed from experimental data. ► The result compared with the prediction of theoretical calculations.The 41 Σ + state in KLi, characterized by a potential energy curve of irregular shape, is investigated experimentally. Spectra of the 41 Σ +  ← X1 Σ + band system, simplified by polarization labelling, are recorded and analyzed. The Inverted Perturbation Approach method is used to construct the exotic molecular potential of the 41 Σ + state. The result is compared with the prediction of theoretical calculations.

The high resolution far-infrared absorption spectrum of CH2D79Br, recorded by Fourier transform spectroscopy employing a synchrotron radiation source, allowed the rovibrational assignment of the v 6 fundamental and hot bands originating from v 6.Display Omitted► High resolution synchrotron far-infrared study of CH2D79Br. ► Rovibrational analysis of the ν 6 fundamental band. ► Upper-state parameters obtained up to sextic order centrifugal distortion terms. ► Analysis of the hot bands originating from v 6. ► Effective upper-state constants determined using v 6  = 1 as lower-state.The high resolution (0.0025 cm−1) far-infrared absorption spectrum for the v 6 (v 0  = 595.0733 cm−1) fundamental band of CH2D79Br has been recorded by Fourier transform spectroscopy employing a synchrotron radiation source. The spectral analysis allowed the assignment of more than 1700 rovibrational transitions attributed to the predominant a-type component. In the same spectral range, the 2v 6  −  v 6 hot band has been analyzed by selecting about 800 transitions. In addition, hot band transitions originating from v 6 have been assigned in region of the v 5 and v 9 fundamentals. The data set of each band was treated using the Watson’s A-reduced Hamiltonian in the I r representation.

Display Omitted►Ultrafast oscillatory electronic motion between two H atoms in a hydrogen molecular ion is induced due to the creation of excited states during the ionization, where the periodicity of electronic oscillation between H atoms is T  = 225 as.In this Letter we report a method for controlling electronic localization in a molecular ion, on an attosecond time scale, using a high-intensity laser, based on two different excitation mechanisms. One takes place during ionization, and the other takes place sequentially, following ionization. The electronic excited states of the hydrogen molecular ion are created during ionization by taking the configuration interaction mixing of neutral molecules into account. We detect the ultrafast oscillatory electronic motion between two atoms in a hydrogen molecular ion occurring due to the creation of excited states during the course of ionization.

Theoretical study on the formation of tetraoxygen conformational isomerism in the CO2 with O3 reaction by Moein Goodarzi; Farideh Piri; Nasim Hajari; Leila Karimi (51-55).
Display Omitted►The reaction mechanism of CO2 with O3 on the singlet potential energy surface has been investigated at the CBS-QB3//B3LYP/6-311++G(3df, 3pd) level. ►The four different structures have been optimized for O4 (O4(C2h), O4(C2V), O4(D2h) and O4(D3h)). ►There is no favorable pathway for the formation of O4(C2h), O4(C2V), O4(D2h) and O4(D3h) in the reaction of CO2  + O3.The reaction mechanism of CO2 with O3 on the singlet potential energy surface has been investigated at the CBS-QB3//B3LYP/6-311++G(3df, 3pd) level of theory. The reactants are initially associated with adducts IN1 (OOO–OCO) and IN2 (OC–cyclic O4) in a barrier-less process. Then, adducts undergo isomerization and dissociation processes to produce P1 (CO + 23O2) and P2 (CO3  +  3O2) with two different mechanisms. The calculated results show that there is no favorable pathway for the formation of these two products in the atmospheric reaction of CO2 with O3.

The IR spectrum obtained by CPMD simulation for the 2-acetyl-1,8-dihydroxy-3,6-dimethylnaphthalene.Display Omitted► For the strong intramolecular hydrogen bond very large delocalization of bridging proton is noted, especially in the path integral simulation where quantum effects are taken into account. ► No tautomerism was found for this intramolecular hydrogen bond. ► Geometry optimization at the PBE1PBE/6-311++G(2d,2p) level demonstrate the existence of two tautomers on the potential energy surface.Theoretical studies of the structure and proton motion in the intramolecular O–H…O hydrogen bonds in 2-acetyl-1,8-dihydroxy-3,6-dimethylnapthlane were carried out at the DFT and molecular dynamics levels. Geometry optimization at the PBE1PBE/6-311++G(2d,2p) level demonstrate the existence of two tautomers on the potential energy surface. Dynamics of proton motion in intramolecular hydrogen bonds was investigated in vacuo at 100 K using Car–Parrinello and path integral molecular dynamics. For the strong intramolecular hydrogen bond very large delocalization of bridging proton is noted, especially in the path integral simulation where quantum effects are taken into account. No tautomerism was found for this intramolecular hydrogen bond.

Display Omitted► Organic glasses of exceptional thermodynamic and kinetic stability have been prepared for the first time for four substances by vapor deposition in simple sublimation apparatus. ► This study demonstrates the generality of the phenomenon and possibility to prepare these interesting materials economically. ► Substances forming stable glasses by vapor deposition tend to undergo surface-enhanced crystal growth, suggesting both phenomena could be linked to surface mobility.Organic glasses of exceptional thermodynamic and kinetic stability have been prepared for the first time for four substances by vapor deposition in simple sublimation apparatus. This study, together with previous studies, demonstrates the generality of the phenomenon; the simple apparatus makes these interesting materials more accessible for research. Substances forming stable glasses by vapor deposition tend to undergo surface-enhanced crystal growth, suggesting both phenomena could be linked to surface mobility. Stable organic glasses are potentially useful for drug delivery, organic electronics, and thin-film technologies.

Display Omitted►H⋯H close contacts are shown to be stabilizing rather than destabilizing steric clashes in a series of Zn(II) complexes in solution. ►These close-contacts exhibit all the hallmarks of chemical bonding: Bond paths of maximal electron density linking the nuclei of the two hydrogens, elevated delocalization indices of interacting hydrogen atoms, and considerably lower atomic energy of the hydrogen atoms involved in such interaction when compared to similar hydrogens that lacks such a bond path. ►The difference between bond path angles and geometrical bond angles is found to be strongly correlated with the 6-member coordination rings strain energy and formation constants. ►Unexpectedly, the bite angle N–Zn–O is found to be the least strained.Two H⋯H close contacts, classically associated with steric hindrance, were found to be H–H closed-shell bonding interactions which stabilize a zinc(II) complex with nitrilotri-3-propanoic acid, [Zn(NTPA)(H2O)2], by ca. 11 kcal/mol in aqueous phase. The strain energy of three 6-member rings (ca. 40 kcal/mol) is significantly offset by these interactions the presence of which is indicated by the presence of a bond path, an elevated delocalization index, and a lowering of the atomic energy of each hydrogen atom involved in an H⋯H interaction by ∼4–5 kcal/mol. The difference between relevant bond path angles and geometrical bond angles in the 6-member coordination rings correlates well with strain energy and formation constants. Unexpectedly, the bite angle N–Zn–O is found to be the least strained.

The percentage of uncomplexed Cyclodextrin in equilibrium with the micellar system depends on the balance between surfactant complexation and self-assembly.Display Omitted► β-CD binds alkyl sulfonates forming 1:1 host-guest complexes. ► Uncomplexed β-CD is present in equilibrium with the micellar system. ► Decreasing the hydrophobicity of the surfactant increases the percentage of uncomplexed cyclodextrin.Mixed systems formed by surfactants, sodium alkylsulfonates, and β-cyclodextrin have been studied by using the solvolysis of 4-methoxybenzenesulfonil chloride (MBSC) as a chemical probe. The kinetic analysis allows us to obtain the percentage of uncomplexed cyclodextrin in equilibrium with the micellar media and its variation with the alkyl chain length of the surfactant. Competition between surfactant complexation by the cyclodextrin and self-aggregation to form micelles is the driving force for the percentage of uncomplexed cyclodextrin in equilibrium with the micellar system and its variation with the surfactant chain length.

Total (a) and Fe (b) number of states η per Fe atom of the CuInS2:Fe chalcopyrite for the spin-up (+) and spin-down (−) alignments and ferro/antiferro spin alignment.Display Omitted► In this manuscript the electronic and magnetic properties of the ferromagnetic and antiferromagnetic Fe-doped chalcopyrite are analyzed. ► LDA, GGA, LDA + U and GGA + U first principles GGA/LDA and GGA/LDA + U are reported and compared. ► The results agree very well with the experimental results.The Fe-doped CuInS2 could have important applications for photovoltaic or spintronic applications. This material has been analyzed from first principles with the local density and the generalized gradient approximation, as well as with a Hubbard term. The effect on the electronic and magnetic structure has been carried out for both ferromagnetic and antiferromagnetic spin alignments. The results compare well with the experimental ones.

Display Omitted►Results of computer simulations indicate that the water contribution contrasts the pairwise hydrophobic interaction of fullerene molecules. ►The decrease in water accessible surface area upon association causes both a gain in configurational/translational entropy of water molecules and a loss of a significant fraction of fullerene–water attractive energetic interactions. ►The latter term proves to be larger in magnitude than the former because the density of carbon atoms on the fullerene molecular surface is markedly greater than that of normal hydrocarbons.Makowski et al. determined the potential of mean force for the association of two fullerene molecules in TIP3P water, at room temperature, and found that the water contribution contrasts pairwise hydrophobic interaction. In the present Letter this result is rationalized by showing that the decrease in water accessible surface area upon association causes both a gain in configurational/translational entropy of water molecules and a loss of a significant fraction of fullerene–water attractive energetic interactions. The latter term proves to be larger in magnitude than the former because the carbon atom density on fullerene molecular surface is markedly greater than that of normal hydrocarbons.

The minimum energy path (MEP) showing the dissociation of the strongest adsorbed O2.Display Omitted► The adsorption of O2 is less stable and the adsorbed O2 gets fewer electrons on the Pt3Ni(1 1 1) surface as compared with that on Pt(1 1 1). ► The diffusion and dissociation of O2 on Pt3Ni(1 1 1) surface become more difficult. ► Possible mechanisms for the enhanced ORR of the Pt3Ni catalyst are proposed.The adsorption, diffusion and dissociation of O2 on the Pt-skin Pt3Ni(1 1 1) surface were investigated using the ab initio density functional theory (DFT) calculation. The adsorption of O2 is less stable and the diffusion and dissociation of the adsorbed O2 are weakened as compared to those on the Pt(1 1 1) surface. The mechanism for the high oxygen reduction reaction (ORR) activity of the Pt3Ni(1 1 1) surface is attributed to the weakening the adsorption of OH and other oxygenous intermediates produced by ORR, which therefore alleviates the poisoning to the catalyst.

Display Omitted► 1-Butyl-3-methylimidazolium octyl Sulfate (bmimOs) forms micelle in EAN. ► The CMC of bmimOs in EAN was nine times greater than the CMC of bmimOs in water. ► Micelle formation has little effect on the interaction between the ions of RTIL. ► Even at three times CMC the average solvation time increases only by a factor of 4.65.We have investigated the micelle formation by room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium octyl sulfate (bmimOs) with another RTIL, ethyl ammonium nitrate (EAN). In addition, the effect of micelle formation on the solvation and rotational relaxation dynamics have been observed using steady-state and picoseconds time-resolved spectroscopy. Both the solvent and rotational relaxations of Coumarin-153 are retarded in the micelle compared to that of neat EAN. The increase in average solvation time on going from neat EAN to bmimOs-EAN micelle is very small compared to the increase in solvation time on going from pure water to water containing micelle.

Raman spectroscopic and optical imaging of high spin/low spin domains in a spin crossover complex by Salma Bedoui; Gábor Molnár; Sylvestre Bonnet; Carlos Quintero; Helena J. Shepherd; William Nicolazzi; Lionel Salmon; Azzedine Bousseksou (94-99).
Display Omitted► The [FeII(bapbpy)(NCS)2] complex shows a two-stepped spin-state transition. ► Raman mapping reveals nucleation and growth of domains of molecules in the same spin state during the two transitions. ► Elastic stress and strain are evidenced throughout by polarized light microscopy. ► The first transition is characterized (on the observation scale) by a single nucleation site and domain growth along the c axis. ► An interplay between ‘twin domains’ and ‘spin domains’ is revealed for the second transition.Using optical microscopy and various contrast methods we have investigated the spatio-temporal development of the two-step spin transition in single crystals of the [Fe(bapbpy)(NCS)2] complex. Nucleation and growth of domains displaying different molecular spin states were directly inferred from Raman spectroscopic images. The high-temperature transition proceeds in most cases by nucleation at a macroscopic defect, followed by growth along the c axis of the crystal. The development of elastic strain and associated birefringence are proved by polarized light measurements. The low-temperature transition is accompanied by the onset of twinning, which leads to a particular multi-domain growth mechanism.

On the absorption properties of the excited states of DMABN by Ignacio Fdez. Galván; M. Elena Martín; Manuel A. Aguilar (100-102).
Display Omitted► LE state absorptions have been calculated in vacuum and water with CASPT2. ► The computed absorption energies agree very well with experimental values. ► A πσ∗ state is not needed to explain the excited state absorption spectrum.There is some recent controversy on whether the excited state absorption spectrum features of DMABN can be explained only with the two excited states responsible for the dual fluorescence in this compound. We have performed CASPT2 calculations on the optimized π π ∗ excited state in gas phase and in water. The results reproduce the main experimental features of the spectra, leading to the conclusion that the participation of another excited state of different nature is not needed to explain the observed absorption bands.

3D COFs (COF-102 and COF-108), despite their rigid 3D network structures, were found to exhibit relatively low elastic stiffness overall, presumably due to their high porosity and low density. In particular, COF-108, the least dense crystal known, exhibits rather low bulk and shear moduli (B  = 4.9 GPa and G  = 1.0 GPa), raising the question as to whether or not COF-108 can keep its structural integrity after fully removing the guest molecules from the as-synthesized sample.Display Omitted► We found that 2D COFs with layered structures prefer shifted AA stacking, which is different from the straight AA stacking that was generally proposed previously. ► The shear moduli of 2D COFs are exceedingly small (<0.5 GPa), comparable to highly defective graphite, suggesting that the layer–layer coupling in 2D COFs is rather weak, and stacking faults may widely exist in the actual materials. ► Representative 3D COFs were found to exhibit relatively low elastic stiffness overall, presumably due to their high porosity and low density. ► COF-108, the least dense crystal known, exhibits rather low bulk and shear moduli, raising the question as to whether or not COF-108 can keep its structural integrity after fully removing the guest molecules from the as-synthesized sample. ► Our findings provide important structural and physical details to be considered in the further development of COF materials.We report the first investigation of the structural stabilities and elastic properties of covalent organic frameworks (COFs), a new class of porous crystalline materials. Representative 2D COFs were found to prefer shifted AA stacking, somewhat similar to graphite. The shear moduli of 2D COFs are exceedingly small, suggesting that the layer–layer coupling in 2D COFs is rather weak, and stacking faults may widely exist. Representative 3D COFs were found to exhibit relatively low elastic stiffness overall. In particular, COF-108, the least dense crystal known, exhibits rather low bulk and shear moduli. Our findings provide important structural and physical details to be considered in the further development of COF materials.

Excited state electronic polarization and reappraisal of the n ← π∗ emission of acetone in water by Yoelvis Orozco-González; Kaline Coutinho; Sylvio Canuto (108-112).
Display Omitted►Analysis of the solvent effect on the n ← π∗ emission of acetone in water is made. ► Solute-solvent configurations generated by Monte Carlo simulation are used. ► Electronic polarization in the excited state is systematically included. ► The excited state dipole moment in-solvent agrees with Car-Parrinello dynamics. ► The results conform that the solvent effects on the fluorescence of acetone is mild.Electronic polarization of the acetone molecule in the excited n → π∗ state is considered and its influence on the solvent shift in the emission spectrum is analyzed. Using an iterative procedure the electronic polarizations of both the ground and the excited states are included and compared with previous results obtained with Car–Parrinello dynamics. Analysis of the emission transition obtained using CIS(D)/aug-cc-pVDZ on statistically uncorrelated solute–solvent structures, composed of acetone and twelve explicit water molecules embedded in the electrostatic field of remaining 263 water molecules, corroborates that the solvent effect is mild, calculated here between 80 and 380 cm−1.

Display Omitted► Structural properties of zinc(II) solvation complex in dimethyl sulfoxide solution. ► Combined analysis of XANES and EXAFS spectra. ► Octahedral geometry with a Zn–O distance of 2.10 A and a Zn–O–S angle close to 120°.The solvation structure of the zinc(II) ion in dimethyl sulfoxide has been determined by studying both the EXAFS and XANES regions of the Zn K-edge absorption spectra. The combination of these two techniques has proved to be very powerful for the complete structural determination of the solvated complex in DMSO solution. The comparison between the experimental and theoretical data has demonstrated that the solvation sphere of the zinc(II) cation is formed by six dimethyl sulfoxide molecules arranged in an octahedral fashion with a Zn―O first shell distance of 2.10(3) Å and a Zn―O―S angle close to 120 ° .

Matrix-isolation infrared spectra of HOOBr and HOBrO produced upon VUV light irradiation of HBr/O2/Ne system by Nobuyuki Akai; Daisuke Wakamatsu; Takeo Yoshinobu; Akio Kawai; Kazuhiko Shibuya (117-120).
Display Omitted►HOOBr and HOBrO are generated by the VUV photolysis of HBr/O2 isolated in a Ne matrix. ►IR bands of HOOBr and HOBrO are assigned by isotope-labeled experiments and CCSD calculation. ►Both isomers of HOOBr and HOBrO are found to decompose upon UV irradiation.Vacuum ultraviolet (VUV) light photolysis of an HBr/O2 mixture in a Ne matrix has produced HO2Br isomers (HOOBr and HOBrO), which are important reaction intermediates in atmospheric chemistry. The observed bands have been assigned with an aid of a quantum chemical calculation at CCSD/aug-cc-pVDZ. These assignments have been confirmed by the experimental results using isotopic species of 18O2 or DBr. Their characteristic bands are discussed in comparison with those of HOOCl and HOClO from an HCl/O2 mixture . Both HOOBr and HOBrO are found to be photolyzed with the UV light below 385 nm.

Display Omitted► Two pulse correlation in ultrafast transient absorption spectroscopy. ► New photo-isomerization path of Indocyanine Green including multiphoton process was found. ► Control of reaction efficiency was realized by changing interval between two pump pulses. ► Multiphoton isomerization was found by two pulse correlation of transient absorption. ► Optical order in photoreaction path was revealed by asymmetric two pulse correlation.In cyanine dye, a photo-isomerization path involving a multiphoton process was found in addition to a conventional reaction path with a one-photon process by two-pulse correlation of transient absorption and bleaching. That photo-isomerization was completed within 3 ns and its efficiency was dependent on the interval time between two pump pulses indicate that the new path involves a multiphoton process: S 0  →  Sn  →  Sm , where Sn is ∼3.1 eV and Sm is ∼4.7 eV higher than S 0 and the lifetime of intermediate state in Sn is approximately 0.2 ps. Changing the pump power controlled the branching ratio between the two paths.

Hybrid density functional theory calculations of oxygen vacancy formation in the CeO2 (1 1 0) and (1 0 0) surfaces are presented.Display Omitted► This is the first hybrid density functional theory study of surface oxygen vacancy formation in the (1 1 0) and (1 0 0) surfaces of ceria. ► Comparing with previous DFT + U studies, vacancy formation energies are underestimated with DFT + U, but formation of localised Ce3+ ions is found with both methods. ► The position of the Ce3+ state in the band gap is much improved with hybrid DFT, which may have implications for the reactivity of these surfaces in catalytic reactions.In ceria the formation of oxygen vacancies plays a key role. Density functional theory, corrected for on-site Coulomb interactions (DFT + U) provides a reasonable description of oxygen vacancies, but has issues with the U dependence. We present a hybrid HSE06 study of oxygen vacancies in the (1 1 0) and (1 0 0) ceria surfaces. We find (i) the oxygen vacancy formation energy is larger with hybrid DFT compared with DFT + U, (ii) localised Ce3+ ions form and (iii) the position of the Ce3+ gap state is in good agreement with experiment. Our results provide important information for assessing the reliability of the DFT + U approach.

Formation and microstructural characterization of In2O3 sheath layer on InN nanostructures by Hung Bae Ahn; Young Heon Kim; Moon Deock Kim; Chang Soo Kim; Jeong Yong Lee (131-135).
Display Omitted► Rounding and bursting phenomena were observed during the oxidation process. ► InN/In2O3 core-shell structures were identified as intermediate structures. ► HRTEM study shows two different atomic structures at the InN/In2O3 interfaces. ► Cracks in burst nanostructures were generated at the corners.An In2O3 sheath layer was formed on an InN nanostructure by a rapid thermal oxidation process. Rounding and bursting phenomena were observed as the progression of the oxidation process was followed. InN/In2O3 core-shell structures were identified as intermediate structures. After a 20 min oxidation, the InN nanostructures were completely transformed to an In2O3 phase. InN and In2O3 had wurtzite (WZ) and body-centered cubic (BCC) structures, respectively. The preferred orientation relationship of <1 1  2 ¯  0>WZ//<1 1 0>BCC and {0 0 0 1}WZ//{ 1 ¯  1 1}BCC was observed between InN and In2O3. Cracks in burst nanostructures were generated at the corners and penetrated along the <1 1  2 ¯  0> directions.

The interfacial electronic structure of fullerene/ultra thin dielectrics of SiO2 and SiON by S.W. Cho; Y. Yi; K.B. Chung; S.J. Kang; M.-H. Cho (136-140).
Display Omitted► The electronic structures of C60/SiO2 and C60/SiON and energy diagrams are described. ► The surface nitrogen reduces the work function of the SiON compared to the SiO2. ► The LUMO offset is determined by the work function of each dielectric substrate. ► The threshold voltage is related to the work function of the dielectric layer used.The electronic structures at the interface region between fullerene and dielectric layers were investigated by in situ ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). The highest occupied molecular orbital (HOMO) onset of the fullerene layer saturates at 1.3 eV below the Fermi level of the SiO2 layer, which was based on the measurement of the sample with a 12.8 nm thick fullerene layer. On the other hand, the HOMO onset was measured at 2.0 eV below the SiON layer Fermi level. The magnitude of the interface dipole and band bending at the interface was determined, and the complete energy level diagrams for fullerene on SiO2 and SiON were evaluated.

Surface area of closed carbon nanotubes determined from room temperature measurements of alcohols adsorption by Sylwester Furmaniak; Artur P. Terzyk; Roman Gołembiewski; Piotr A. Gauden (141-145).
Adsorption isotherms of alcohols on studied carbon nanotubes.Display Omitted► Alcohols are arranged flat on closed nanotubes. ► Qualitative agreement between surface area of tubes from nitrogen and alcohols is observed. ► Alcohols adsorption can be recommended for surface area measurements as cheaper alternative to nitrogen.The results of systematic study of alcohols (methanol, ethanol, n- and iso-propanol) adsorption on three types of closed carbon nanotubes are reported and described by recently proposed model. The values of specific surface areas determined from adsorption data of alcohols are larger than those obtained from low-temperature nitrogen adsorption however, the qualitative agreement is observed. Therefore it is concluded that alcohol sorption at room temperature is good and cheaper alternative to low-temperature nitrogen measurements.

Display Omitted► Accurate DFT-D calculations have provided unknown molecular packing motifs of newly engineered organic molecular semiconductors based on tetracene. ► Cyanation at central positions has revealed as an efficient way to reduce the coupling between charges and molecular backbone.► Additional selective halogenation also provides large electronic couplings.Computational methods are used recently as reliable tools to uncover the properties of novel conjugated organic materials and understand the physico-chemical mechanism that ultimately controls the overall organic-based device efficiency. Since modelling of charge transport across organic layers needs to address simultaneously single molecule properties together with electronic couplings between neighbouring molecules, which truly depends on the molecular packing, we employ dispersion-corrected Density Functional Theory methods to accurately extract key molecular parameters governing this phenomenon at the nanoscale. It is concluded that controlled functionalization (cyanation and/or halogenation) of state-of-the-art molecules (tetracene) is an efficient way to modulate the charge mobilities.

Graphene analogue BCN: Femtosecond nonlinear optical susceptibility and hot carrier dynamics by Sunil Kumar; N. Kamaraju; K.S. Vasu; Angshuman Nag; A.K. Sood; C.N.R. Rao (152-157).
Figure shows the ultrafast processes that occur after excitation with a femtosecond laser pulse, (a) describes the density of electronics states in BCN and (b) shows the electronic transitions in the conical bands at K points in graphene, (c) shows the typical carrier distributions after various relaxation processes at ultrafast time scales.Display Omitted► First ultrafast laser experiments on newly synthesized material namely BCN (boron–carbon-nitrogen), a graphene analogue, are reported. ► The photoexcited carrier dynamics in graphene and BCN are shown to be different. ► Nonlinear absorption in graphene and BCN are also different; namely saturable absorption in graphene and optical limiting in BCN. ► Third order optical nonlinear coefficients in addition to the ultrafast carrier relaxation times show that BCN can be a potential candidate for ultrafast nonlinear optical applications such as optical limiters and fast optical switches.Third-order nonlinear absorption and refraction coefficients of a few-layer boron carbon nitride (BCN) and reduced graphene oxide (RGO) suspensions have been measured at 3.2 eV in the femtosecond regime. Optical limiting behavior is exhibited by BCN as compared to saturable absorption in RGO. Nondegenerate time-resolved differential transmissions from BCN and RGO show different relaxation times. These differences in the optical nonlinearity and carrier dynamics are discussed in the light of semiconducting electronic band structure of BCN vis-à-vis the Dirac linear band structure of graphene.

Display Omitted► Surface-enhanced Raman scattering (SERS) applied to a low-angle beveled surface. ► Achievement of the depth resolution of nearly 5 nm of organic species. ► The first practical application of SERS to an organic light emitting diode.Information on depth distribution of molecular vibrational modes of an organic multilayer device has been obtained by surface-enhanced Raman scattering (SERS) applied to a low-angle beveled surface which was prepared by gradient shaving preparation. We achieved a depth resolution of nearly 5 nm in terms of the decay length of the organic species at the interfaces. Encapsulation with a glass cap after metal deposition in nitrogen atmosphere gives reproducible SER spectra even at 1-μm range.

Features of quantum control in the sudden regime by Michael Klein; Vincent Beltrani; Herschel Rabitz (161-163).
Distributions of P 1 → 10 generated from ten thousand random N = 10 dimensional Hermitian μ matrices. (a) The distribution of P 1 → 10 for all values of β ∈ [ 0 , 1000 ] without optimization. (b) The distribution of the maximum value of P 1 → 10 after optimizing over β ∈ [ 0 , 1000 ] . The mean yield increases from 0.09 in (a) to 0.52 after optimization over β in (b).Display Omitted► Computational studies demonstrate that optimization of one parameter dramatically improves the distribution of yields for quantum control in the sudden regime. ► The simplified dynamics of quantum control in the sudden regime affords experimental flexibility to optimize multiple objectives including minimization of a competing pathway. ► With control over the dipole entries, perfect yields can be obtained in the sudden regime along with excellent robustness.Although quantum dynamics in the sudden regime is generally not fully controllable, the simple dependence of the observable yield on the applied field enables efficient searches for a control and also admits generally many solutions. This flexibility allows for simultaneous optimization of ancillary objectives including the minimization of competing pathways throughout the control period. These features are illustrated with simple models and simulations.

Complete basis set limit extrapolation calculations with PNOF3 by J.M. Matxain; M. Piris; X. Lopez; J.M. Ugalde (164-167).
Complete basis set (CBS) extrapolated total energies are calculated for the ground state and lowest-lying excited state with different spin for Li to Ne using the recently developed spin-conserving PNOF3 natural orbital functional. The extrapolated values are very accurate and reproduce near 100% of the total energy.Display Omitted► Complete basis set extrapolation by PNOF3 for C singlet and triplet states. ► High-accuracy compared to CCSD(T) results. ► CCSD(T) values are lower-bounds.Complete basis set (CBS) extrapolated total energies have been calculated for the ground state and lowest-lying excited state with different spin of the second-row atoms (Li–Ne) using the recently developed spin-conserving PNOF3 natural orbital functional. CBS results are obtained by extrapolating power and exponential functions to the results obtained using the correlation-consistent aug-cc-pVTZ, aug-cc-pVQZ and aug-cc-pV5Z basis sets. The extrapolated total energy values are very accurate as compared to the benchmark data, and reproduce near 100% of the total energy. Interestingly, the benchmark data are lower bounds for the PNOF3 results. Finally, we have found that the calculated PNOF3 excitation energies are very accurate as comparing with both their corresponding CCSD(T, full) values and their experimental marks.

Assessment of Gaussian-4 theory for energy barriers by Larry A. Curtiss; Paul C. Redfern; Krishnan Raghavachari (168-172).
Display Omitted► Gaussian-4 theory using QCISD/MG3 geometries has good accuracy for reaction barriers. ► The method has an average absolute deviation of 0.71 kcal/mol for 76 barrier heights. ► G4 theory using B3LYP/6-31G(2df,p) geometries has a larger average absolute deviation.Gaussian-4 (G4) theory, and various modifications, are assessed for the calculation of the heights of reaction energy barriers. The results indicate that G4 theory based on QCISD/MG3 geometries shows good accuracy for the calculation of bond-making and bond-breaking reaction barriers with a mean unsigned deviation of 0.71 kcal/mol for 76 barrier heights involving both hydrogen and non-hydrogen transfer reactions. G4 theory based on B3LYP/6-31G(2df,p) geometries has a larger mean unsigned deviation of 1.36 kcal/mol for the 76 barriers heights due to deficiencies in the geometries of transition states for fluorine-containing systems.

Display Omitted► Mechanism of the oscillating H2O2–KSCN–CuSO4–NaOH system. ► Luminol. ► Time-series ARMA.Oscillations in redox potential and chemiluminescence of the H2O2–KSCN–CuSO4–NaOH system in the presence of luminol were examined. Parts of the mechanism proposed in the previous studies were evaluated by substitution of SCN with CN. The amplitude of the chemiluminescent oscillations was found to be strongly dependent on the initial luminol concentrations. In addition, the time-series ARMA (2;1)-analysis with Box–Jenkins algorithm were used to simulate the system and the result is well in accordance with the observed oscillations.

Display Omitted► Theoretical modeling of charge transfer vibronic transitions. ► Calculation and simulation of absorption spectrum of uranyl in complexes. ► Evaluation of electronic energy levels, energies of local vibrational modes, and vibronic coupling strength of uranyl in complexes.A theoretical model is developed for simulating optical spectra of uranyl in complexes. The spectral profiles of electronic and vibronic transitions of UO 2 2 + bonded to equatorial ligands are evaluated based on the Huang–Rhys theory of vibronic coupling in solids. This model assumes that only the symmetric O=U=O stretching mode exhibits multi-phonon progression, whereas all other local modes are not Franck–Condon allowed and treated as false origins of the progressing mode. A simulation of vibronic transitions in the UO2(NO3)2(TBP)2 complex is compared with absorption spectrum to determine the excited state energy levels, frequencies of local vibration modes and vibronic coupling strength.